class:: Spring
summary:: physical model of resonating spring
categories:: UGens>Filters>Nonlinear, UGens>Generators>PhysicalModels
related:: Classes/Ball, Classes/TBall

description::
models the force of a resonating spring

classmethods::

method:: ar, kr

argument::in
modulated input force

argument::spring
spring constant (incl. mass)

argument::damp
damping


examples::
code::
// trigger gate is mouse button
// spring constant is mouse x
// mouse y controls damping
(
{
	var inforce, outforce, freq, k, d;
	inforce = K2A.ar(MouseButton.kr(0,1,0)) > 0;
	k = MouseY.kr(0.1, 20, 1);
	d = MouseX.kr(0.00001, 0.1, 1);
	outforce = Spring.ar(inforce, k, d);
	freq = outforce * 400 + 500; // modulate frequency with the force
	SinOsc.ar(freq, 0, 0.2)
}.play;
)


// several springs in series.
// trigger gate is mouse button
// spring constant is mouse x
// mouse y controls damping
(
{ 	var m0, m1, m2, m3, d, k, inforce;
	d = MouseY.kr(0.00001, 0.01, 1);
	k = MouseX.kr(0.1, 20, 1);
	inforce = K2A.ar(MouseButton.kr(0,1,0)) > 0;
	m0 = Spring.ar(inforce, k, 0.01);
	m1 = Spring.ar(m0, 0.5 * k, d);
	m2 = Spring.ar(m0, 0.6 * k + 0.2, d);
	m3 = Spring.ar(m1 - m2, 0.4, d);
	SinOsc.ar(m3 * 200 + 500, 0, 0.2) // modulate frequency with the force

}.play;
)

// modulating a resonating string with the force
// spring constant is mouse x
// mouse y controls damping
(
{ 	var m0, m1, m2, m3, m4, d, k, t;
	k = MouseX.kr(0.5, 100, 1);
	d = MouseY.kr(0.0001, 0.01, 1);
	t = Dust.ar(2);
	m0 = Spring.ar(ToggleFF.ar(t), 1 * k, 0.01);
	m1 = Spring.ar(m0, 0.5 * k, d);
	m2 = Spring.ar(m0, 0.6 * k, d);
	m3 = Spring.ar([m1,m2], 0.4 * k, d);
	m4 = Spring.ar(m3 - m1 + m2, 0.1 * k, d);
	CombL.ar(t, 0.1, LinLin.ar(m4, -10, 10, 1/8000, 1/100), 12)

}.play;
)
::